ORDER CYCLOBRANGHIATA. 87 
cula, and the sides of the foot are furnished with a range of 
filaments. 
EMARGINULA, Lam. 
The structure of the emarginule is similar to that of a 
fissurella, except that instead of the hole in the summit, 
there is a small cleft or emargination in the anterior margin of 
their mantle and shell, which also penetrates to the branchial 
cavity ; the margin of the mantle envelopes and covers a great 
part of that of the shell; the eyes are placed on a tubercle of 
the external base of the conical tentacula, and the margin of 
the foot is furnished with a range of filaments. 
PARMOPHORUS, Lam. 
A great portion of the shell curved by the reflected margin 
of the mantle, as in the emarginule ; the shell itself oblong, 
slightly conical, and without hole or emargination ; the bran- 
chiz and other organs, as in the preceding genera. 
NINTH ORDER OF GASTEROPODA, 
CYCLOBRANCHIATA. 
THE branchiz of the cyclobranchiata resemble small lamelle, 
or little pyramids forming a cordon, more or less complete, 
under the borders of the mantle, very nearly as in the infero- 
branchiata, from which they are distinguished by the nature of 
their hermaphroditism ; for, like the preceding genus, they 
